I have a buddy who can sell me a complete lower frame for an M18c. His slide is in his FPG conversion kit. I have the complete version of the FPG and need to know if the FPG slide will work with the M18c lower. I know that some internals have been tweeked in the complete FPG kit so I don't know if it will work with the old M18c lower.

I have put my FPG Complete slide/barrel onto my m18c lower frame. It works fine; functions as my m18c does. It's hideous, the longer outer barrel on such a short frame AND slide looks hideous, but none the less they work (based on my experience).